Known AC-to-DC converter architectures comprise a first boost power factor correction (PFC) converter stage receiving an alternating current (AC) rectified voltage and a second DC-to-DC voltage converter stage, whereby the two stages are interconnected through a direct current (DC) link capacitor. Generally the intermediate bus voltage (between the two stages) is fixed to 400V, high enough to guarantee the boost operation for EU mains voltage considering the line variations (365V in the worst case).
Applications requiring a high level of integration of power conversion modules, for example using Switched Mode Power Supplies (SMPS), can resort to power converters such as Switched Capacitor Converters (SCC) for the DC-to-DC voltage converter stage, which can provide highly efficient DC-to-DC voltage conversion with only the use of capacitors and switches, combined with inductive output filters.
Notably, the Solid State Lighting (SSL) Industry's demand for small and compact power management units for LEDs is increasing. LEDs require that a power supply be delivered in the form of a constant current, as efficiently as possible. Ideally, LED drivers comparable in size to the LEDs themselves would represent a significant breakthrough enabling new lighting concepts. Such a solution will require a system with a high level of reliability and efficiency, in order to fit the requirements of life-time, size and heat dissipation.
LED drivers can be based on SMPS. SMPS can comprise SCCs, which allow a high level of integration and achieve large power conversion ratios, but have the drawback of providing plural discrete conversion ratios, which do not make SCCs suitable for applications where a fine regulation of the output power is required.
SMPS can also comprise conventional Inductive Converters, comprising a plurality of inductors and switches. Inductive Converters allow a fine regulation of the output power and can efficiently provide an arbitrary conversion ratio, but one drawback of Inductive Converters is that they cannot be easily integrated in compact structures.
Hybrid Switched Capacitor Converters (H-SCCs) use the pulsed width modulated voltages, available in the internal nodes of SCCs, combined with filter inductors to extend the conversion range and increase the efficiency of the SCCs.